1. Field of the Invention
The present invention relates to attitude sensors for satellites.
2. Discussion of Related Art
The location and orientation of a spacecraft is of critical importance. The location of the spacecraft, for example, may determine its ability to achieve scientific research goals and to transmit/receive important information to Earth, or other spacecraft. Furthermore, the location of a spacecraft may be required to determine the spacecraft trajectory and therefore its future location as well as to plan changes in the trajectory to send the spacecraft to a desired location.
Sensors are provided on satellites for indicating orientation of the satellite. Sensors may be mounted to satellites, space probes and the like, for sensing the Earth, stars and/or sun, and producing signals indicating orientation of the satellite with respect to the Earth (around which the satellite is orbiting), the stars and/or the sun. The sensors are provided for attitude control and guidance. For example, an Earth sensor may be a critical component of a communication or remote sensing satellite""s attitude control subsystem. It may be desirable to maintain a communications or remote sensing satellite in a geosynchronous orbit about the Earth so as to enable a communication beam or sensor field of view from the satellite to accurately cover a desired area, such as a particular country, on the surface of the Earth. Any deviations from this attitude may alter the coverage of the beam or view. As beam size decreases, there is an increasing need for greater accuracy of the satellite and more specifically the pointing direction of antennas.
Embodiments of the present invention may provide a spacecraft that includes a communications payload having an antenna support structure and an antenna boom coupled to the antenna support structure. An attitude sensor may be mounted to a root of the antenna boom. The root may be located at an area where the antenna boom couples to the antenna support system. The attitude sensor may include an Earth sensor and/or a star tracker.
In at least one embodiment, the communications payload may relate to Internet services. A spacecraft bus may support services of the communications payload.
Embodiments of the present invention may also provide a satellite for broadband communications. The satellite may include a communications payload to receive and transmit broadband communications. The communications payload may include an antenna boom. A sensor may be coupled to the payload at a root of the antenna boom.
Other embodiments, objects, advantages and salient features of the invention will become apparent from the detailed description taken in conjunction with the annexed drawings, which disclose arrangements and preferred embodiments of the invention.